8
A.G. Gerbst et al./Carbohydrate Research 417 (2015) 1–10
4
16 mg (21%) of individual 10 as a colourless syrup and a mixture
4.70 (d, 1H, J1,2 7.9 Hz, H-1), 4.49–4.39 (m, 1H, H-6), 4.07 (m, 1H,
H-3), 3.92–3.79 (m, 2H, OCHH’CH CH , H-6′), 3.74–3.63 (m, 1H, H-4),
3.59–3.45 (m, 2H, OHH’CH CH , H-5), 1.64–1.46 (m, 2H, OCH CH CH ),
0.81 (t, 3H, J 7.9 Hz, OCH CH ). C NMR (100 MHz, CDCl ) δ
133.27–126.30 (Ar), 101.92 (CHPh), 101.54 (C-1), 81.00 (C-4), 74.98
(C-2), 72.49 (C-3), 71.98 (OCH CH CH ), 68.68 (C-6), 66.22 (C-5), 22.74
CH ). HRESIMS: found m/z 437.1585;
containing 10 and (2-methyl-5-tert-butylphenyl)-1-thio-β-L-
fucopyranoside (~1:1 according to H NMR data). Data for 10: R
2
3
1
f
0.32
2
3
2
2
3
1
13
(EtOAc); [α]
D
172 (c 1, EtOAc); H NMR (600 MHz, CDCl
3
) δ 7.69–
2
2
CH
3
3
7.04 (m, 3H, SAr), 5.37 (d, 1H, J1,2 2.9 Hz, H-1), 4.28–4.12 (m, 2H, H-2,
H-3), 4.03–3.95 (m, 2H, H-4, H-5), 2.41 (s, 3H, CH
3
Ar), 1.41–1.19 (m,
CAr),
37.33–125.43 (SAr), 92.12 (C-1), 87.07 (C-4), 82.59 (C-2), 78.45 (C-
), 67.32 (C-5), 31.71 ((CH CAr), 20.74 (CH Ar), 20.23 (C-6).
S [M + Na]+
49.1444. Selected NMR data for (2-methyl-5-tert-butylphenyl)-1-
2
2
3
13
1
1
3
2H, (CH
3
)
3
CAr, H-6). C NMR (125 MHz, CDCl
3
) δ 149.97 ((CH
3
)
3
(OCH CH CH
2 2 3
), 10.27 (OCH
2
CH
2
3
+
calcd for C23
H
26
O
7
[M + Na] 437.1571.
3
)
3
3
HRESIMS: found m/z 349.1435; calcd for C17
3
H
26
O
4
3.7. Glycosylation by furanosyl donors 9 and 11 (general procedure)
1
thio-β-L-fucopyranoside: H NMR (300 MHz, CDCl
1,2 9.4 Hz, H-1), 3.71 (d, 1H, J1,2 3.1 Hz, H-4), 3.65 (t, 1H, J2,1 = J2,3 = 9.3 Hz
Hz, H-2), 3.60–3.54 (m, 2H, H-3, H-5), 1.29 (d, 3H, J5,6 6.5 Hz, H-6).
3
) δ 4.42 (d, 1H,
To a mixture of the glycosyl donor (0.06 mmol), glycosyl accep-
tor (0.05 mmol) and 4 Å (200 mg) molecular sieves in anhydrous
CH Cl (2 mL) were added at 0 °C under argon: NBS (27 mg,
2 2
0.15 mmol) and TfOH (1.8 μL, 0.02 mmol). After 30 min, the mixture
was filtered, and successively washed with saturated aqueous
J
13
C NMR (75 MHz, CDCl
3
) δ 88.55 (C-1), 75.03 (C-3, C-5), 71.70 (C-
4
), 70.08 (C-2), 16.68 (C-6).
2 2 3 3 2 4
Na S O , NaHCO , and brine. The organic layer was dried over Na SO
3
.4. (2-Methyl-5-tert-butylphenyl) 2,3,5-tri-O-benzyl-1-thio-β-L-
and concentrated. The residue was purified by column chromatog-
raphy on silica gel (petroleum ether–EtOAc, gradient 8:1→3:1) to
give disaccharides as a mixture of the α- and β-isomers as a
colourless syrup.
fucofuranoside (11)
Exhaustive O-benzylation of 10 (225 mg, 0.69 mmol) as de-
scribed for the preparation of 9 gave product 11 (342 mg, 83%) as
a colourless syrup; R
f
0.52 (Petroleum ether–EtOAc, 5:1); [α]
D
98
3.8. Propyl 2,3,5,6-tetra-O-benzyl-(α,β)-D-galactofuranosyl-(1→3)-
2-O-benzoyl-4,6-O-benzylidene-β-D-glucopyranosides (15α,β)
1
(c 1, EtOAc); H NMR (600 MHz, CDCl
3
) δ 7.79–7.08 (m, 18H, SAr, Ph),
5
1
4
4
3
.64 (d, 1H, J1,2 2.6 Hz, H-1), 4.72 (d, 1H, J 11.8 Hz, CHH’Ph), 4.63 (m,
H, CHH’Ph), 4.56 (m, 2H, CHH’Ph), 4.50 (d, 1H, J 11.9 Hz, CHH’Ph),
.45 (d, 1H, J 11.7 Hz, CHH’Ph), 4.27 (dd, 1H, J3,4 7.0, J4,5 3.9 Hz, H-4),
.21 (t, 1H, J 3.0 Hz, H-2), 4.12 (dd, 1H, J3,4 7.1, J2,3 3.2 Hz, H-3), 3.79–
Glycosylation of glucoside 14 (21 mg, 0.05 mmol) with donor 9
(42 mg, 0.06 mmol) as described in the general procedure gave di-
saccharides 15α,β (37 mg, 79%, α/β = 1.2:1) as a colourless syrup.
1
.74 (m, 1H, H-5), 2.45 (s, 3H, CH
.28 (d, 3H, J5,6 6.4 Hz, H-6). 13C NMR (150 MHz, CDCl
(CH CAr), 137.52–124.49 (SAr, Ph), 89.87 (C-1), 88.95 (C-2), 83.83
C-4), 83.48 (C-3), 73.17 (C-5), 72.25 (CH Ph), 72.07 (CH Ph), 71.23
3
Ar), 1.33 (s, 9H, (CH
3
)
3
CAr), 1.31–
R
f
0.23 (petroleum ether–EtOAc, 2:1); H NMR (selected, 600 MHz,
1
3
) δ 149.55
CDCl
3
) δ 8.10 (d, 2.4H, J = 7.9 Hz, o-C(O)Ph), 8.01 (d, 2H, J = 7.9 Hz,
α-fur
(
(
(
)
3 3
o-C(O)Ph), 5.59 (s, 1H, PhCH), 5.56 (d, 1.2H, J1,2 = 4.3 Hz, H-1 ), 5.44
(s, 1.2H, PhCH), 5.45–5.39 (m, 2.2H, 2 × H-2 ), 5.25 (s, 1H, H-1 ),
pyr
β-fur
2
2
CH
2
Ph), 31.36 ((CH
3
)
3
Car), 20.34 (CH
3
Ar), 16.08 (C-6). HRESIMS:
1.63–1.46 (m, 4.4H, OCH
2
CH
2
CH
3
2 2 3
), 0.84–0.72 (m, 6.6H, OCH CH CH ).
+
13
β-fur
found m/z 619.2844; calcd for C38
H
44
O
4
S [M + Na] 619.2853.
3
C NMR (selected, 150 MHz, CDCl ) δ 105.25 (C-1 ), 101.80 (2 × C-
pyr
α-fur
1
), 101.75 (PhCH), 101.59 (PhCH), 100.27 (C-1
), 22.68
3.5. Propyl 4,6-O-benzylidene-β-D-glucopyranoside (13)
(OCH
calcd for C57
2
CH
2
CH
3
), 10.25 (OCH
2
CH
2
CH
3
). HRESIMS: found m/z 959.3970;
+
H
60
O
12 [M + Na] 959.3977.
Benzaldehyde dimethyl acetal (154 μL, 1.03 mmol) and (+)-CSA
(
1
15 mg, 0.065 mmol) were added to a solution of propyl glucoside
2 (152 mg, 0.68 mmol) in dry CH CN (3 mL). The mixture was stirred
for 3 h at 45 °C, then neutralized with Et N and the solvent was
3.9. Propyl 2,3,5-tri-O-benzyl-(α,β)-L-fucofuranosyl-(1→3)-2-O-
benzoyl-4,6-O-benzylidene-β-D-glucopyranosides (16α,β)
3
3
evaporated in vacuo. The residue was purified by column chroma-
tography (silica gel, toluene–EtOAc, 2:1) to give diol 13 (181 mg, 84%)
Glycosylation of glucoside 14 (21 mg, 0.05 mmol) with donor 11
(36 mg, 0.06 mmol) as described in the general procedure gave di-
as a white solid. R
f
0.72 (EtOAc); [α]
) δ 7.64–7.19 (m, 5H, Ph), 5.53 (s, 1H, CHPh), 4.39
d, 1H, J1,2 7.8 Hz, H-1), 4.34 (dd, 1H, J5,6 4.9, J6,6′ 10.5, Hz, H-6), 3.90–
.74 (m, 3H, OCHH’CH CH , H-3, H-6′), 3.58–3.49 (m, 2H,
OCHH’CH CH3, H-4), 3.48–3.40 (m, 2H, H-5, H-2), 1.73–1.59 (m, 2H,
OCH CH CH
CDCl ) δ 137.00–126.30 (Ph), 103.15 (CHPh), 101.88 (C-1), 80.58 (C-
), 74.52 (C-2), 73.11 (C-3), 72.08 (OCH CH CH ), 68.69 (C-6), 66.35
C-5), 22.86 (OCH CH CH ), 10.36 (OCH CH ). HRESIMS: found
m/z 333.1307; calcd for C16
D
−70 (c 1, EtOAc); 1H NMR
saccharides 16α,β (34 mg, 83%, α/β = 2:1) as a colourless syrup. R
0.25 (petroleum ether–EtOAc, 2:1); H NMR (selected, 600 MHz,
f
1
(400 MHz, CDCl
3
(
3
CDCl
3
) δ 8.15 (d, 2H, J = 8.1 Hz, o-C(O)Ph), 8.10 (d, 1H, J = 8.0 Hz,
2
3
o-C(O)Ph), 5.62 (s, 0.5H, PhCH), 5.57 (s, 1H, PhCH), 5.56 (s, 0.5H,
β-fur
pyr
2
H-1 ), 5.50 (t, 1H, J2,1 = J2,3 = 8.3 Hz, H-2 ), 5.39 (d, 1H, J1,2 = 3.9 Hz,
1
3
α-fur
pyr
2
2
3
), 0.96 (t, 3H, J 7.4 Hz, OCH
2
CH
2
CH
3
). C NMR (100 MHz,
H-1
OCH
OCH
150 MHz, CDCl
101.76 (PhCH), 101.59 (C-1pyr), 97.98 (C-1α-fur), 22.67 (OCH
), 5.33 (t, 0.5H, J2,1 = J2,3 = 8.7 Hz, H-2 ), 1.60–1.48 (m, 3H,
fur
3
2
CH
CH
2
CH
CH
3
), 0.85 (d, 1.5H, J6,5 = 6.4 Hz, H-6 ), 0.81–0.77 (m, 4.5H,
), 0.72 (d, 3H, J6,5 = 6.2 Hz, H-6fur). C NMR (selected,
13
4
2
2
3
2
2
3
β-fur
pyr
(
2
2
3
2
CH
2
3
3
) δ 106.05 (C-1
), 101.99 (C-1 ), 101.85 (PhCH),
CH CH ),
). HRESIMS: found
54
H O11 [M + Na] 853.3558.
+
H
22
O
6
[M + Na] 333.1309.
2
2
3
fur
fur
1
5.37 (C-6 ), 15.24 (C-6 ), 10.19 (OCH
m/z 853.3556; calcd for C50
2 2 3
CH CH
+
3.6. Propyl 2-O-benzoyl-4,6-O-benzylidene-β-D-glucopyranoside
(
14)
3.10. Methyl 2,3,5,6-tetra-O-benzyl-(α,β)-D-galactofuranosyl-
A mixture of diol 13 (169 mg, 0.54 mmol) and Bu
.65 mmol) in anhydrous toluene (10 mg) was refluxed with
azeotropic removal of H O to a volume of 4 mL. The mixture was
2
SnO (162 mg,
(1→3)-2-O-benzoyl-4,6-O-benzylidene-β-D-galactopyranosides
(18α,β)
0
2
cooled to RT and treated with BzCl (75 μL, 0.65 mmol), kept for 1 h
and then concentrated under reduced pressure. The residue was pu-
rified by column chromatography (silica gel, toluene–EtOAc, 5:1)
Glycosylation of galactoside 14 (19 mg, 0.05 mmol) with donor
9 (42 mg, 0.06 mmol) as described in the general procedure gave
disaccharides 18α,β (33 mg, 73%, α/β = 1.5:1) as a colourless syrup.
1
to give monosaccharide 14 (140 mg, 62%) as a white solid. R
f
0.48
R
f
0.61 (toluene–EtOAc, 4:1); H NMR (selected, 600 MHz, CDCl
3
)
1
(
toluene–EtOAc, 3:1); [α]
D
−14 (c 1, EtOAc); H NMR (400 MHz, CDCl
3
)
δ 8.11 (d, 2H, J = 7.2 Hz, o-C(O)Ph), 8.02 (d, 3H, J = 7.2 Hz, o-C(O)Ph),
pyr
δ 8.30–7.15 (m, 10H, Ph), 5.60 (s, 1H, CHPh), 5.23–5.18 (m, 1H, H-2),
5.70 (dd, 1.5H, J2,3 = 9.8 Hz, J2,1 = 8.4 Hz, H-2 ), 5.63 (dd, 1H,